The email from the RSC (who hosted the original run) has two quotes:
'Magnificent… the finest Kneehigh production I have seen' Five stars Financial Times
'There's nothing to beat this company at their inventive best' Time Out
.. to which I have two comments:
How many Kneehigh productions have they seen? Just looking at their recent stuff, Brief Encounter, Cymbeline, and Nights at the Circus were all much better than this.
I would almost agree with the second (Improbable are better, but not much else) however alas Don John is not them at their inventive best.
The basic idea is interesting - take Don Giovanni, update it a bit (they've set it in the late 1970s), emphasise the women (who all retain their names from the opera, whereas all the men's names are changed) and... well it goes a bit wrong from there.
Including snatches of the opera only serves to remind you that it is better than this (disclaimer: it's my favourite opera) and I'll see if I can refind the review I agreed with that for some strange reason the RSC isn't quoting.